On LNT and Nuclear Energy

January 11th, 2010
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Sure, the Linear Non-Threshold Hypothesis is not exactly supported by scientific evidence, and it was simply created as a “worst case” model for radiation exposure, since emperical data on low exposure was, at one time lacking. Admittedly, it can be difficult to screen out the statistical noise when it comes to verifying or refuting effects as trivial as those which LNT predicts for low exposure. Even if the model was correct, it would predict that the dangers of getting a dental x-ray would be on par with those of spending a few minutes in a smokey bar or eating a large box of french fries. Still, what data we have managed to acquire has generally refuted, rather than supported LNT.

Still, LNT does not seem to be going anywhere and many agencies have adopted it as their standard for evaluating radiation exposure. It might be said that it could serve as the absolutely worse, even unreasonably bad case for the potential for radiation’s health effects.

Some will use LNT as a means of opposing nuclear energy. Various special interests and extremists like Ernest J. Sternglass insist that nuclear energy can’t be tolerated because the effects of even the low levels radiation on the public are intolerable. Sure, even the supporters of the model have to admit that by their most liberal estimates the increased risk of cancer from living near a nuclear power plant is only a tiny fraction of a percent, but they insist that this is something that should not be imposed on the public and even one death is too many.

Okay, so lets, for the sake of argument, assume LNT is correct (which it isn’t). If we accept that this is the case, then there are a few outcomes from this. First, we will have to admit that it’s impossible to avoid radiation entirely, since it is – after all, your body emits radiation from the carbon-14 and potassium-40 in your food. Secondly, we will have to realize that there are human activities that increase our exposure to radiation and that these vary in their magnitude. Since we can’t tackle all of them, or at least, we can’t all at once, we will have to figure out what our priories should be when it comes to reducing exposure by as much as we can.

(From the Lawrence Berkley National Laboratory)

So how do we get our radiation exposure down as low as we can?

1. Phase out coal, as fast as possible and replace it with nuclear power – What? Replace it with nuclear power to reduce radiation? Indeed, that would be the first thing to do, because there is no greater source of enviornmental radiation than coal burning and that is before we even consider all the other nasty things that coal brings with it. Nuclear power produces some radiation, but the amounts are orders of magnitude less than coal. The average person receives only a tiny amount of exposure from the fuel cycle, and even those who live next door to a nuclear plant receive less exposure than from a coal plant. Since coal is so huge, we must replace it at once and do so with a source that is as low in radioactivity as possible. Gas is lower than coal, but nuclear is even lower, so that’s the most logical thing to do.

2. Eliminate nuclear medicine or place extremely tight regulations on it – Sure, when most think of the kinds of facilities that are most likely to expose them to radiation, they probably think of power plants first, but the fact of the matter is that hospitals and cancer treatment centers emit far more radiation into the local enviornment. These facilities use highly concentrated and potent radio-nucleotides for therapeutic purposes and for imaging as well. Many of the things that hospitals flush down the toilet or allow patients to go home with in their bodies are of an activity high enough to get a nuclear plant in big trouble if it were ever emitted into the enviornment.

For example, technetium-99 is a fission byproduct with a halflife of 211,000years. It’s one of the nucleotides that environmentalists complain storage sites like Yucca Mountain can’t be expected to keep under wraps for thousands of years and worse still, it’s “unnatural.” Yet when used in the form of technigas for medical imaging, patients are allowed to just exhale it into the atmosphere! Clearly this cannot be allowed.

Complete elimination of nuclear medicine would seem the best way to go. Of course, X-rays and other imaging procedures that use ionizing radiation should also be high on the list. Yet doing so would obviously cost many many lives. How can we reconcile this? In light of this, the best solution would be to hold hospitals to the highest standards possible for medical waste that could contain artificial radioactivity. They will have to suck up all that gas and filter it from the air, keep patients for months in confined lead-lined rooms until their levels return to normal and take whatever measures are necessary to keep the public from exposure. Since medical institutions suffer far far more radiation incidents and accidents than nuclear power plants, they will have to be located in isolated areas with multiple layers of barriers from the public and environment.

The consequence of this will, of course, be that therapies will be much more expensive, far less avaliable and also more difficult on patients. Getting a PET scan will involve some time away from family, perhaps being transported to a remote island and cared for by doctors behind many inches of leaded glass, touching the patient only with telemanipulators, less they get even a tiny exposure to the radioactivity.

But this is a far far more important step than addressing nuclear energy.

3. Take extreme steps to reduce radon – Sure, it’s natural, but it’s also the single largest source of radiation exposure to many people around the world. Radon occurs as a decay product of uranium. Uranium is extremely common in the earth’s crust and therefore radon is too. It tends to collect in low lying areas and can be found in many homes with a basement or cellar. In most cases, the levels are considered too low to warrant any action, but since we’re going to adopt the same standpoint that allows anti-nuclear activists to oppose nuclear energy on the grounds that it causes radiation, we must address first a source of much greater radiation.

All homes will have to have their floors sealed and have pump systems installed to pull as much radon as physically possible out of their foundations before it seeps into the living space. However, homes are not the only place these systems will be needed. What about the children? Since they have no choice where they are educated or visit, buildings like schools, libraries and other public spaces will need to be delt with first. They’ll need the most extreme measures taken to reduce radon as much as is possible.

Of course, we will need to build more nuclear power plants to power all the pumps and vacuums that will be sucking out the radon. That’s fine though, because the contribution to public exposure will be minuscule and thus this large reduction in radon will result in a huge net reduction, even given the increase from the nuclear fuel cycle. That’s also not to mention that mining uranium will mean less uranium to decay to radon in nature.

Some radon can be found outdoors, but that’s going to be all but impossible to deal with. The only potential solution: since radon is heavy and tends to be found near the ground, people are advised to wear a “snorkel” like device consisting of a breathing tube that will extend several feet into the air.

4. Tear down and bury all granite and most masonry structures – Granite contains uranium and thorium in high concentrations. Most Portland cement does too and this means that masonry buildings are a big no-no. Sure, it may be a choice to live in one, but what of the children? Children attending school may be subject to exposure from any granite used in their schools construction, any mortar used to hold the bricks together, cinder blocks and even the tile in the boys and girls bathroom! This is a far greater exposure than nuclear energy might produce, even if they live in the same town as a nuclear plant.

The answer is clearly that all municipal and school buildings made of granite need to be torn down immediately and their rubble buried. Buildings made of cinder blocks come next and then comes brick. After we complete this, we can begin tearing down office buildings and private homes. They’re a high priority too, but perhaps not as high, as people have some choice as to whether or not to live in them.

But what shall we replace them with? We could look for sources of low-uranium cement, perhaps chemically processed to remove most of it and drawn only from quarries with bellow-normal levels of uranium and thorium. Metal would be another good choice. Good, high purity, electro-refined metal should have a pretty low level of uranium or other radioactive materials in it. And since we need to do this all quickly (for the children) we’ll need to find a structure that can be built in mass. The answer?

Clearly it is the quaoset hut.

5. End the use of natural gas – No, it does not expose the public to as much radiation as burning coal, but it does expose the public to far more radiation than nuclear energy and if it’s used for cooking in the home it can be a significant source.

Not only does natural gas contain trace amounts of radioactive materials that can result in exposure by its end use, the drilling and exploration process can bring highly radioactive materials to the surface. These materials may be more dangerous than nuclear spent fuel, because unlike spent fuel, which is a chemically inert, nonsolutable, dense ceramic that is encased in corrosion-resistant cladding, these natural radioactive materials have a potentially high biological uptake and can be mobile in the environment.

6. Reduce exposure from flying – Flying is not a choice for everyone, after all, cancer patients will need to get to the hospitals that are located in the middle of nowhere and the air crew certainly don’t have a choice in flying and thus exposing themselves to dangerous cosmic radiation. There are, however, steps that can be taken to reduce the radiation exposure from high altitudes. First, aircraft will have to keep to low altitudes. Bellow five thousand feet there will be signifficantly less cosmic radiation. Aircraft can also be covered with lead foil, to further reduce radiation exposure. This will obviously increase weight, so there will be a need to use more powerful engines and reduce the capacity of the aircraft to allow them to continue to fly. It is worth it, however, because aviation is a far more dangerous source of radiation.

This will, however, result in much higher fuel consumption and given that crude oil is already prone to supply crunches, there will need to be some means of providing the massive, low-flying aircraft will need. The answer is to build more nuclear reactors to produce synthetic fuels. Sure, this will result in a tiny contribution to radiation exposure, but since doing so will allow us to keep radiation levels from aviation, a much greater source, so much lower, it will be a huge net reduction.

7. Find and isolate all consumer products that have significant radioactivity – It might seem like a trivial amount of radiation exposure, but it’s far greater than a nuclear plant would expose anyone to. If we are of the mindset that nuclear plants are too dangerous, then these items are going to be absolutely disastrous. Workers with Geiger counters will have to survey every buisiness and home and remove anything suspicious. Your grandfather’s old watch with a radium dial will need to go, as will any orange colored pottery or dinner plates from before the mid 1980′s. Many will find that their bathroom tile needs to be ripped out and granite countertops are another big one that’s going to need to come out. Even false teeth may need to be confiscated.

Once all these items are collected, they’ll have to be isolated and buried deep in the earth’s crust where they can’t harm anyone. It might seem like a big loss to those left with no counter-tops, no teeth, no smoke detectors and tile floors ripped out, but if we’re so keen on protecting the public from radiation, these have to go!

8. Ban highly radioactive foods – Another big source of exposure and far bigger than nuclear power. Sure, we may not be able to get the levels down to zero, but we can reduce them a bit. Brazil nuts are obviously going to need to be banned, because they contain radium. Areas of the world with higher than average soil radioactivity will be off limits for farming and most importantly, we’ll have to keep potassium intake to a bare minimum.

Potassium is a vital nutrient, so unfortunately, we can’t have zero, but given that all natural potassium contains potassium-40, we’re going to want to keep uptake to the minimum nutritional requirements. For this reason, bananas are going to need to be registered with the federal government, as are all other items that are high in potassium. No more substitute salt, so if your blood pressure is high, you better get used to food that is just plain bland.

In the longer term, there will need to be some better solution to eliminate as much potassium from the diet as possible. The answer is clear: eat only foods that are very low in potassium and provide for the nutritional requirements using artificial supplements that are made of isotropically enriched potassium, virtually free of k-40. Eventually, isotope separation plants will be built to remove carbon-14 and other dangerous radioactive isotopes from food.

9. Stop using aquifers in areas with natural occurring radioactive materials – Another source of exposure, and far bigger than nuclear energy is water. Much of the world’s drinking water supply comes from underground aquifers, but many of these have traces of uranium, radium, thorium and other natural radioactive materials in them. In all but the most extreme circumstances, the levels are well bellow safety standards, but if we are concerned about nuclear energy then we must be much more concerned about this and that means that the use of any water with significant amounts of radioactive produces will need to end.

Alternative water supplies can be provided by distilling sea water or pumping in water from areas of low geological radioactivity. In some cases, well water may still be acceptable, but only after it has gone through multiple cycles of filtering and distillation. To this end, we’ll need to build a number of nuclear plants to provide the energy for filtration, distillation and pumping of all that water.

10. Phase out nuclear energy – By the time we’ve tackled all these issues, we’ll have built a lot of nuclear plants, because they’re the lowest radiation means of providing the energy necessary to keep people away from radiation. However, they do result *some* exposure to radioactivity. It’s tiny, but after we’ve tackled all the bigger issues, we’ll need to address this one. Somehow we’ll need to find a source of energy that is even lower in radioactivity than nuclear energy and that will be a challenge.

Given the relative exposure, this should be of the lowest priority. Only after every granite monument has been torn down and the rubble burred in deep caverns, away from civilization, only after the last building has had an active radon removal system installed, only after the last piece of orange antique pottery has been isolated from humans and disposed of should this tiny issue even be considered.

With all the other sources taken care we’ll have only this little one left. The answer will be damming up every river we possibly can, cultivating hugh areas to provide bio-fuels (but without phosphate fertilizer, because that’s radioactive) and construction of millions of wind turbines. Of course, we’ll have to consider whether the concrete used in the construction of the wind turbines and dams might result in *more* radiation exposure. Trying to find a lower exposure method of power generation than nuclear energy is really setting the bar very very, perhaps impossibly, high.

This may not be feasible, however, and we’ll need to accept the tiny amount from nuclear energy as a trade off to protect us from the much larger sources.

Conclusion:

If you are hell-bent on believing that ionizing radiation is dangerous at any level and needs to be kept to a minimum, there are many things you have reason to oppose, but nuclear energy isn’t one of them, or at least, is very low on the list, even to the point of being not worth dealing with until you have managed to rid the world of all radioactive consumer products, all coal burning, all natural gas burning, all granite construction and all bananas. Once you’re done doing that, then maybe we can talk about nuclear energy as a radiation source, but worrying about it now, or even considering it worth taking into account is not justifiable based on the numbers.

Being concerned about radiation exposure and focusing your energy on nuclear energy makes about as much sense as being concerned about cholesterol and therefore eating steak and fried chicken, rather than salad, because you’re concerned about the cholesterol in the salad dressing.


This entry was posted on Monday, January 11th, 2010 at 4:17 pm and is filed under Bad Science, Culture, Enviornment, Good Science, Nuclear, Obfuscation, Politics. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.
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48 Responses to “On LNT and Nuclear Energy”

  1. 1
    DV82XL Says:

    Yes. That is one of the best plans I have seen to date to deal with this LNT nonsense – push it to its ridiculous conclusion.

    Radiation safety is yet another area where money and careers are tied up over-managing the risk. While there is no doubt that there is a hazard both with emitters and from prompt radiation at higher levels, LNT has allowed it to be taken to extremes, and as you have so eloquently illustrated, only at random.

    This was clearly underlined by a recent quote by Mike Clark, scientific spokesman for the British Health Protection Agency as reported in the Guardian in response to Oxford Prof. Wade Allison, who is questioning the validity of the LNT. Clark said:

    “There is an international scientific consensus about the health effects of ionising radiation which is based on decades of research worldwide. This is the so-called linear hypothesis, by which you extrapolate health effects observed at high doses to calculate risks at low doses. There are scientists who disagree with this and clearly Professor Allison is one of them. However there are also some scientists who claim the linear hypothesis can underestimate risks.”

    “The Health Protection Agency accepts the scientific consensus and bases its advice on recommendations from the International Commission on Radiological Protection.”

    In other words the standard is going to be set by a group of people who depend on the acceptance of the LNT hypothesis for their continued employment.


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  2. 2
    Q Says:

    Thus, you argue that nuclear energy is the best form of energy because it is lower in radiation than most others? Interesting view.

            DV82XL said:

    Radiation safety is yet another area where money and careers are tied up over-managing the risk. While there is no doubt that there is a hazard both with emitters and from prompt radiation at higher levels, LNT has allowed it to be taken to extremes, and as you have so eloquently illustrated, only at random.

    If radiation safety is the concern, then is it a valid question to ask that more effort go into reducing the larger emitters? From my understanding, living next to a nuclear plant will expose you to around 1-2 mrem extra per year, and living a few miles away it’s like .1 mrem per year.

    If the radiation exposure from consumer products (welding rods, lantern mantles, tiles, antique watches, kitty litter, pottery) is 10 mrem, then logically it stands to reason that for every dollar a group spends to try to get rid of nuclear energy, they should spend one hundred dollars toward efforts to eliminate thorated welding rods and bathroom tile, no?


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  3. 3
    DV82XL Says:

    It not just nuclear energy that has suffered. At a minimum LNT has created astronomical expenses in the public and private sector attempting to protect the population from dangers that are not really there. It has severely limited the use of therapeutic radiation treatments and hobbled the development of new ones. It has severely limited the use of radiation to reduce spoilage in food, and to disinfest food shipments of vermin.


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  4. 4
    gmax137 Says:

    That pie-chart should be hanging on the wall of every 7th grade classroom in the country.

    Or maybe not – I can imagine the teacher pointing to it, and telling the class, “Look, the ‘Nuclear Fuel Cycle’ is the second from the top…” Best to not underestimate the innumeracy of the general public. We are doomed.


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  5. 5
    Carl Willis Says:

    Although I appreciate that DC has brought a lot of sense to bear against radiophobic hysteria, the linear-no-threshold (LNT) model has a well-established scientific basis and a domain of validity. I also dispute that the logical outcome of this relationship is that we must reduce exposure “as much as we can” ad absurdum.

    Specifically, the LNT model applies to radiation carcinogenesis (stochastic effects). It was developed using data from a-bomb survivors in Japan, from people irradiated to treat ankylosing spondylitis, from children epilated for ringworm with x-rays, from women treated with x-rays for postpartum mastitis, and some other sources. From Hall E, “Radiobiology for the Radiologist,” 5th Ed. (2000) p. 162-163: “[T]he probability of an effect increases with dose, with no dose threshold…” I am not going to quote the entire body of data, or the nuances of the LNT model’s range of applicability, but will merely refer interested parties to this common and respected textbook for further details.

    In radiation protection programs, ALARA (“As Low As REASONABLY Achievable”) is the operative philosophy derived from the LNT model that concerns radiation exposure. This does NOT mean reducing exposure as far as one possibly can, but only within the bounds of reason; nobody with an objective understanding of risk in perspective would curtail potassium from their diet, eliminate their smoke detectors, tear up their granite countertops, or take other such perverse measures.

    -Carl


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  6. 6
    ondrejch Says:

    It seems there are some developments in mainstream media too: “Irrational fears give nuclear power a bad name, says Oxford scientist. Wade Allison says misplaced health stigma has prevented the full benefits of nuclear energy being explored.”

    http://www.guardian.co.uk/environment/2010/jan/10/nuclear-power-irrational-fears


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  7. 7
    DV82XL Says:

            Carl Willis said:

    Although I appreciate that DC has brought a lot of sense to bear against radiophobic hysteria, the linear-no-threshold (LNT) model has a well-established scientific basis and a domain of validity.

    After World War II, the details were released of the A-bombing of Japan. Studies of atomic bomb survivors from Hiroshima and Nagasaki, showed a linear relationship between cancer mortality and high doses of radiation as a result fallout hysteria became one of the themes of the times. The situation was not helped by lurid stories of several high dose incidents reported in the press. Health Physics and Genetics were supported lavishly by radiation fears, and Radiation Biology became the most intensely researched science in history. Health physicists soon learned that their livelihood depended upon scaring funds out of governments and science became irrelevant if the paymasters wanted to mislead the public about the hazards of radiation. If a particular study failed to find evidence of radiation’s ill effects, the data was simply forced into the LNT model. Yet some of these studies are among the best evidence for radiation hormesis because the authors were not looking for it, and effectively denied that it existed.

    The LNT model was first considered in the 1940s purely on the theoretical grounds that a single hit by ionizing radiation on a single cell could cause chromosome damage that could cause a mutation or cancer without any hard evidence to support that contention. The justification for using the LNT model was that too many test animals or too much time would be needed to evaluate chronic dose rates. If the LNT model is correct, there is no “no observed adverse effect level” (NOAEL) for regulators to observe, thus officials responsible for public health can claim justification in calling for minimization of exposures to ionizing radiation. Note that this is tantamount to saying that avoiding sunlight is justified on the grounds that nobody will get sunburns in the dark. Added to this, during the Cold War a number of people promoted the LNT model in an attempt to discourage nearly all uses of nuclear weapons and nuclear power, and used it as leverage in their campaigns.

    As a result the radiophobes and the politicians took a handy but false rule of thumb and enshrined it in law and regulation. The second problem, related, is that this results in a lot of stupid but expensive procedures where people and vendors can make a lot of money thus entrenching this false standard through special interests.

    In spite of this atmosphere, during the 1960’s and 1970’s, about 40 articles per year described hormesis. In 1963, the AEC repeatedly confirmed lower mortality in guinea pigs, rats and mice irradiated at low dose. In 1964, the cows exposed to about 150 rads after the Trinity A-Bomb test in 1946 were quietly euthanized because of extreme old age. This trend continues. It was found that there was decreased cancer mortality in government nuclear facility workers in Canada, the UK, and the US. Whether exposed in uranium mines or processing plants, laboratories, or nuclear power plants—and whether the exposure was to uranium, plutonium, thorium or radium, so long as the dose was 50 times background (chronic) or, 50 rad acute, workers were healthier than those in the general population, mainly due to lower cancer incidence. Decreased cancer mortality, decreased leukemia rate, decreased infant mortality rate and increased lifespan in atomic bomb survivors from both Hiroshima and Nagasaki who received 1.2 rad. was found and a 20% lower cancer death rate in Idaho, Colorado and New Mexico, which have background radiation of 0.72 rad/yr compared with Louisiana, Mississippi and Alabama with 0.22 rad/yr was also reported. There were many other similar examples as a quick look through the literature will reveal.

            Carl Willis said:

    I also dispute that the logical outcome of this relationship is that we must reduce exposure “as much as we can” ad absurdum.

    You also have no sense of the absurd yourself, if you cannot recognize sarcasm when you read it.


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  8. 8
    drbuzz0 Says:

            Carl Willis said:

    Although I appreciate that DC has brought a lot of sense to bear against radiophobic hysteria, the linear-no-threshold (LNT) model has a well-established scientific basis and a domain of validity. I also dispute that the logical outcome of this relationship is that we must reduce exposure “as much as we can” ad absurdum.

    Fair enough. I’ve come short of saying that LNT has been disproven outright, because it’s very hard to collect data that low and screen it from the statistical noise, but it’s been used far out of proportion. It is routinely used to oppose any nuclear power or for that matter, anything that involves nuclear materials in general.

    Yet at the same time, while they same parties that will penny-pinch every little micro-rem and say it’s unacceptable to expose the public to even a single photon, using this as their justification for why nuclear is bad bad bad, they’re willing to go into granite buildings, eat bananas, fly in airplanes and everything else that exposes them to much much more radiation.

            Carl Willis said:

    In radiation protection programs, ALARA (“As Low As REASONABLY Achievable”) is the operative philosophy derived from the LNT model that concerns radiation exposure. This does NOT mean reducing exposure as far as one possibly can, but only within the bounds of reason; nobody with an objective understanding of risk in perspective would curtail potassium from their diet, eliminate their smoke detectors, tear up their granite countertops, or take other such perverse measures.

    ALARA makes sense if you have a reasonable definition of the word “reasonable” but there are people (for example Ernist Sternglass and his “radiation and public health” group) who will use a level of radiation lower than what you get exposed to from a counter top as amunition to demand stricter “accountability” for nuclear plants.

    Is it reasonable to place restrictions on a nuclear facility for radiation emissions that are so tight that Grand Central Station would fail them because of the marble and concrete it’s built of? Is it fair to claim that a nuclear plant is irridiating local residents when it is producing less exposure than a single barbecue pit? Why do they not apply such standards to those.

    IF you are going to stand on the principle that many anti-nuclear activists do, then you must believe that radiation is so dangerous that no cement mixer, no kitty litter manufacturer, no banana farmer or antique dealer or tile installer should be allowed to expose the public to many many times more radiation.

    I’m not targeting this at reasonable people. Reasonable people already realize that the radiation from the nuclear fuel cycle is neglidgable.


    BTW: Weird co-incidence. I’ve never seen your website before today, but while writing this article I was hitting up Google images looking for pictures to illustrate it with. While looking for an open-source image of radioactive consumer products, I came across this website called “Special Nuclear Materials” which I then looked at and thought to myself “Wow, this is one awesome site.”

    Then the author of the site comes by and comments on the very post that got me looking at his website that day.

    Is this a coincidence? yeah, it is ;-)

    Still weird.


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  9. 9
    Carl Willis Says:

    Yet some of these studies are among the best evidence for radiation hormesis because the authors were not looking for it, and effectively denied that it existed.

    DV82XL, do you have a citation for any of this stuff? It sounds like propeller-head conspiracy-theory material to me.

    It was found that there was decreased cancer mortality in government nuclear facility workers in Canada, the UK, and the US.

    This is discussed in the Hall book I previously referenced, on p. 161. Basically, that effect is not attributable to radiation but to quality-of-life issues and is well-understood. I won’t belabor the details here, but if you want to get the citations I will oblige via email. I do recommend that anyone desiring a basic understanding of radiobiology read that Hall book. Most university bookstores carry it (because many radiology, oncology, and medical physics classes use it), and it is a very accessible read if you passed basic algebra and have a tad bit of patience.

    There were many other similar examples as a quick look through the literature will reveal.

    Would just be cherry-picking. I can cherry-pick the literature for evidence that smoking promotes longevity… Anyway, I don’t dispute some limited evidence has been found for “hormesis,” but a fair assessment of what’s out there is that it doesn’t lay a hand on the broad, evidence-based, predictive ability of the no-threshold models, and certainly doesn’t discredit the conservative philosophy of ALARA in industrial radiation protection. The day may come when data is good enough to discern a threshold below which radiation exposure has no risk (and may have benefit). That day has not come.

    You also have no sense of the absurd yourself, if you cannot recognize sarcasm when you read it.

    I see no sarcasm involved. DC’s point was that the LNT model compels absurd radiation-protection measures. He obviously doesn’t believe those measures in his example to be appropriate, but his erroneous conclusion is that the LNT model is responsible. Misunderstanding risk is responsible, and the LNT model has nothing to do with that.

    -Carl


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  10. 10
    DV82XL Says:

    Carl – I not going to dodge you, but it’s late here and I have to be someplace early in the morning, so please take a raincheck for this discussion, which I really want to have with you and I will bring references to the table.

    TTFN

    DV8


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  11. 11
    drbuzz0 Says:

            Carl Willis said:

    Would just be cherry-picking. I can cherry-pick the literature for evidence that smoking promotes longevity… Anyway, I don’t dispute some limited evidence has been found for “hormesis,” but a fair assessment of what’s out there is that it doesn’t lay a hand on the broad, evidence-based, predictive ability of the no-threshold models, and certainly doesn’t discredit the conservative philosophy of ALARA in industrial radiation protection. The day may come when data is good enough to discern a threshold below which radiation exposure has no risk (and may have benefit). That day has not come.

    What exactly is your point? If you’re trying to validate LNT all the way down to zero with empirical data, I very much doubt you’ll find that to be possible. If we accept that there’s a linear factor working here and that the total risk of, lets say cancer, is going to be something like .04% increased per whole body rem for the lifetime of the individual in question, then you’re talking about some very small numbers.

    Then each milirem represents an increase of .0004% and each microrem .0000004%. You’re going to need a hell of a lot of case-control studies with total radiation dose measured to an extreme amount of precision to get anything out of that for empirical data to validate it.

    Of course, in practice it’s even more complicated than that since not all tissues are as sensitive to radiation and the stage in life that a person is exposed to it at is going to also make a difference, not to mention all the other factors involved.

    Look, a few years ago I was talking to a friend of mine who was smoking and as a kind of joke she blew a puff of smoke in my face. To get right back at her, I sucked up the cloud smoke and blew it right back at her. By doing that, according to some models, I increased my lifetime risk of lung cancer. Do I obsess over that one incident? Do I even care? No, not at all, because it was so minuscule it’s close to zero!

            Carl Willis said:

    I see no sarcasm involved. DC’s point was that the LNT model compels absurd radiation-protection measures. He obviously doesn’t believe those measures in his example to be appropriate, but his erroneous conclusion is that the LNT model is responsible. Misunderstanding risk is responsible, and the LNT model has nothing to do with that.

    -Carl

    See:

    http://www.radiation.org/

    http://www.nukewatch.com/Quarterly/fall00/f00underware.html

    http://www.helencaldicott.com/childrenshealth_proc.pdf

    http://www.mindfully.org/Nucs/2003/Strontium-90-Sternglass8nov03.htm

    http://www.nirs.org/mononline/beirletter2.htm

    On the last site listed it states:
    “Although the panel is charged with reviewing the Linear-No-Threshold (LNT) model of radiation risk, to the best of our knowledge, the NAS has not appointed a single supporter of the strict LNT model to the panel. NAS staff filled the panel with people who have staked out positions, often very vigorously, advocating that the LNT model overstates risks, while simultaneously excluding all scientists who believe current risk estimates understate the risks. ?”

    Clearly they’re using it as the basis of wholesale disapproval of nuclear energy.

    “There is no safe threshold for radiation” -Helen Caldicott

    From this site: http://www.karlgrossman.com/Articles.htm

    “Also to help in a nuclear power comeback is the effort to alter the standards for radiation exposure. As more has been learned about radioactivity, the realization has come that there is no “safe” level. This is called the “linear no-threshold theory,” and it has been adopted by the NRC and other U.S. government agencies.

    Now nuclear advocates in government and industry want to alter the standards premised on a contention that low doses of radiation are not so bad after all. “

    LNT is also cited as reason by Harvey Wasserman to oppose nuclear energy in his essay “No Nukes Means Better Health” in which he contends that even if the radiation only fills a few people in the world, it’s still unethical – forgetting that there are many other sources of radiation.

    Are you therefore denying that anti-nuclear activists use the “there is no safe level” to oppose nuclear energy?

    Furthermore, are you denying that they apply this unequally to nuclear energy, which they believe is intolerable, while they are silent on fiesta-ware and grout?


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  12. 12
    Carl Willis Says:

    Hi Dr. Buzz,

    Then the author of the site comes by and comments on the very post that got me looking at his website that day.

    Is this a coincidence?

    It’s a small world.

    I’ve been by DepletedCranium many times and I like what you do here. (Mad props on the name too.) I do think the antinuke folks are increasingly distant from reality in many of their pursuits. But I also think that it is in part to the movement’s credit (the part that IS reality-based, anyway) that nuclear power is as safe in the West as it has been. In the Soviet Union, where civilian oversight was nonexistent and critical technical publications were marginalized, the product was far inferior in safety and reliability, and managers justified grave accidents as unavoidable (e.g. Andronik Petrosyants, chairman of the State Committee on the Use of Nuclear Energy, who said in the wake of Chernobyl that “science requires victims.”) If there’s one nation that I think we can extol as a nuclear success story, it would be France. They reprocess their fuel, their air is clean, they export energy, their safety record is excellent. Now EDF is (as some would say) “soshulized.” I suspect that government control is in large part responsible for the nuclear success story there. Did I say that? Oh no! Cue th’ trollage in five, four, three, two…

    -Carl


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  13. 13
    Joseph Hertzlinger Says:

    There’s an obvious way to limit human exposure to radioactivity: Use up as much uranium as possible now. Every unfissioned uranium atom will eventually release 50 MeV of radiation. The fission products will release less than half that.


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  14. 14
    Joseph Hertzlinger Says:

    I suspect that government control is in large part responsible for the nuclear success story there. Did I say that? Oh no! Cue th’ trollage in five, four, three, two…

    Of course there’s a connection. The government is unlikely to regulate its own stuff out of existence. It’s similar to the case with fossil fuels: Nations with state oil companies generally don’t restrict offshore oil drilling.

    One way to achieve a minimal degree of government involvement is, of all things, loan guarantees. They can be considered to be regulation insurance. If a government stands to lose money (that might be used to buy votes) if it passes preposterous regulations, it has an incentive not to do so. (If any readers of this blog can figure out a better way to stop regulations before they start, I’d like to know what it is.)


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  15. 15
    Carl Willis Says:

    What exactly is your point? If you’re trying to validate LNT all the way down to zero with empirical data, I very much doubt you’ll find that to be possible.

    The accepted data currently supports the conclusion that the added risk = zero intercept is statistically not different from dose = zero. This isn’t saying that the true relationship between added risk and dose passes through the point (0,0). Data conclusively revealing a hormetic effect may come to light. Data revealing an identical no-threshold relationship is impossible to obtain, ever; there will always be statistical uncertainty.

    You obviously understand that.

    Anyway, my point was to respond to the other dude’s invitation to cherry-pick. Hormesis has its adherents, some of whom are scientifically responsible. However, it isn’t generally supported by data.

    Are you therefore denying that anti-nuclear activists use the “there is no safe level” to oppose nuclear energy?

    No, I don’t deny that. These guys’ arguments are often based on a misunderstanding of risk, and they actively promote a lopsided, emotional, and scientifically-unjustifiable approach to risk. Just because they cite the LNT model doesn’t mean they draw supportable conclusions from it, or have the slightest understanding of it at all. Now if they want to live their own lives hiding from every single photon (and shorten their lives in the process), they are welcome to do that, just as I am welcome to take a freaking bath in gamma rays day in and day out from my uranium collection and maybe shorten my life a smidgen in the process.

    The LNT model is fine, and will weather the stupidity and misinterpretations surrounding it.

    -Carl


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  16. 16
    drbuzz0 Says:

            Carl Willis said:

    Hi Dr. Buzz,

    It’s a small world.

    BTW: That’s a nice little setup you have put together in that NIM bin for the spectroscopy. What are you using for software to put the data on the PC?

    I’m also a little jealous of some of the items in your collection, I have to admit. Really, it’s the CP-1 graphite that makes me green with envy. Most of the other stuff I either have something similar or of equivalent cool-ness, but the CP-1 graphite is like the holy grail of memorabilia. I would never even have bothered looking for something like that for sale, because as I understood it, there is very little left and it’s the kind of thing museums are lucky to have.


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  17. 17
    Franck Says:

    EDF (french electricity production) or Areva (mining, conditionning and reprocessing of uranium) are not perfect either. From the stories that make it to the newslets, they seem to have a bad tendancy towards using undertrained and underquipped low bidding contractors for hazardous tasks in the name of quaterly profit (yes, EDF is mostly owned by the french state, but, as anyone else, the current government needs fresh cash), The number of recent or planned reactors is too low to account for the planned end of life of the first generation ones (plus, the two EPR plants in constructiuon are slowed down by bureaucracy) or the current unexpectably high number of reactors down when the demand is exceptionnaly high (it is very cold in europe since a month or so and 1/3rd of french households or offices use electricity as their main heat source).

    The direct consequence was that they had to import electricity and shut down rural areas a few times to prevent grid overheating, in particular in Bretagne, where an odd aliance between vocal independentists and hippies ecologists has left millions of people with a mostly renewable local production set that, even theorically, can only produce less than 10% of their needs. All of this because these nuts opposed to any nuclear devices to protests against the submarine base that ironically is still there.

    Anyway, I still prefer our situation to the one of the germans.


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  18. 18
    Ken Says:

    Cigarette smoke contains Polonium 221, the potash used to fertilize it has higher than background levels and the leaves concentrate it. You should move smoking to near the top of your list of things that will need to be eliminated.


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  19. 19
    gmax137 Says:

    Well way up in the original post by drbuzz0 the logic was:

    IF you accept the LNT
    THEN you should be more concerned with:
    (laundry list of radiation sources)
    BEFORE you worry about dose from nuclear power plant

    It’s a simple “pareto” argument: Concentrate your efforts of the big hitters first.

    Since the anti-nukes do not do this, the conclusion is: their use of the LNT as an argument is not reasonable.

    All the subsequent posts about LNT pro or con, while interesting, do not affect the logic of the original post.


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  20. 20
    Calli Arcale Says:

    Hilarious example of reducto ad absurdum. ;-) That is the logical consequence of LNT. Of course, actual real experts simply use LNT as a convenient surrogate for better data and do not assume that there is no safe level. They understand the difference between “no safe level” and “we don’t know how much the body can tolerate but have a pretty good idea that somewhere around here is probably a safe assumption for now, and this LNT thing makes the math way easier”.

    Mind you, the idea of low-flying aircraft isn’t totally absurd. The Soviets experimented heavily with the idea, even building a fair number of what they called “ekranoplanes”, and Boeing has lately been tossing the concept around as well. The idea there is to actually *save* fuel by exploiting ground effect. It’s really not practical over land, but if you’re not in a huge rush, it can result in much more fuel-efficient trans-oceanic travel (assuming you avoid any high seas; these aircraft fly low enough that high seas would actually present a problem). Boeing’s concept was superior to the ekranoplanes in that it would be capable of flying at more normal altitudes as well, allowing it greater flexibility as well as the ability to get out of danger when waves get tall.

    The vehicle would mostly be useful for cargo. They tried to interest the military, but the thing’s massive vulnerability when in ground effect mode was a major negative. Also, designing a totally new type is expensive. It may happen someday, but not soon. And definitely not for radiation concerns. ;-)


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  21. 21
    drbuzz0 Says:

            Calli Arcale said:

    Mind you, the idea of low-flying aircraft isn’t totally absurd. The Soviets experimented heavily with the idea, even building a fair number of what they called “ekranoplanes”, and Boeing has lately been tossing the concept around as well. The idea there is to actually *save* fuel by exploiting ground effect. It’s really not practical over land, but if you’re not in a huge rush, it can result in much more fuel-efficient trans-oceanic travel (assuming you avoid any high seas; these aircraft fly low enough that high seas would actually present a problem). Boeing’s concept was superior to the ekranoplanes in that it would be capable of flying at more normal altitudes as well, allowing it greater flexibility as well as the ability to get out of danger when waves get tall.

    The vehicle would mostly be useful for cargo. They tried to interest the military, but the thing’s massive vulnerability when in ground effect mode was a major negative. Also, designing a totally new type is expensive. It may happen someday, but not soon. And definitely not for radiation concerns. ;-)

    There’s flying in ground effect and then there’s just flying at the lowest altitude you can reasonably get away with and still have descent safety and maneuverability. I saw a video a long while back regarding testing of the B-1 (i don’t remember if it was the B-1A or B-1B program) where it was demonstrating the terain-following radar and autopilot system. It was going down the center of a ravine in the Southwest at just slightly bellow the speed of sound. I’m not sure the altitude, but one of the “wow” shots were one where it had to climb to get enough clearance over an outcropping of tall pine trees and then go over a ridge and back down into the revine.

    Of course this is not for radiation protection. They were showing the system at its extreme and the purpose is to avoid radar and make most surface to air weapons useless. Most SAM’s are not designed or programmed to go after a target that low and won’t be able to track it from ground clutter. Of course, if there was a low level threat to be avoided, the final shot showed the aircraft swing the wings all the way back, light the afterburners and take off at a steep angle up.


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  22. 22
    DV82XL Says:

            Carl Willis said:

    The accepted data currently supports the conclusion that the added risk = zero intercept is statistically not different from dose = zero. This isn’t saying that the true relationship between added risk and dose passes through the point (0,0). Data conclusively revealing a hormetic effect may come to light. Data revealing an identical no-threshold relationship is impossible to obtain, ever; there will always be statistical uncertainty.

    [snip]

    The LNT model is fine, and will weather the stupidity and misinterpretations surrounding it.

    -Carl

    In striking contrast to risk modeling based on gathering as much useful real-world data as possible, the field of radiation risk assessment, has been based principally on unverifiable assumptions and speculations.

    The failure of regulatory agencies during the past four decades, when risk assessment was first applied to radiation regulations, to resolve in reasonable measure these uncertainties has led to a protectionist philosophy in which conservative assumptions became accepted at each point in the risk assessment process. The cascade of risks resulting from such a protectionist stance has resulted in increasingly stringent standards whose benefits and risks cannot be adequately measured but whose costs are often extraordinarily high. It is this decoupling of the potential risks from the financial cost needed to avoid those risks that sets the field of radiation risk assessment apart from the rest of the healthcare world. And although the costs for industry and the public keep growing, there is little evidence or hope of progress despite numerous published texts and journals and the many thousands of professionals engaged in detailed study and evaluation.

    In the fields of biology and medicine hormesis is defined as an adaptive response of cells and organisms to a moderate (usually intermittent) stress. There is evidence supporting hormesis as a mechanism responsible for the health benefits of a variety of lifestyle and environmental factors. This is best documented for exercise which increases the resistance of musculoskeletal and cardiovascular systems to injury and disease. Hormesis is used by toxicologists to refer to an adaptive dose response to an environmental agent characterized by a low dose stimulation. It is this last, more restrictive definition that I will be using here.

    Extensive epidemiological studies have indicated that radiation hormesis is really exist. In 1980 the first complete report on radiation hormesis was published (Luckey TD 1980). In this report he reviewed numerous articles regarding radiation hormesis. Since the first reports, 3000 papers have been published on the benefits of low doses of ionizing radiation (for a review see Luckey 1980, Luckey 1982, Luckey 1991, Radiation Hormesis Overview).* The concept of radiation hormesis is usually applied to physiological benefits from low LET radiation in the range of 1-50 cGy total absorbed dose (Macklis 1991).

    The Académie des Sciences — Académie nationale de Médecine (French Academy of Sciences — National Academy of Medicine) stated in their 2005 report concerning the effects of low-level radiation ( Dose-effect relationships and estimation of the carcinogenic effects of low doses of ionizing radiation that many laboratory studies have observed radiation hormesis. While most major studies have used LNT, the French study concerning the effects of low-level radiation rejected LNT as a scientific model of carcinogenic risk associated for doses less than 100 mSv. They consider there to be several dose-effect relationships rather than only one, and that these relationships have many variables such as target tissue, radiation dose, dose rate and individual sensitivity factors. They propose that more study is done on low doses (less than 100mSv) and very low doses (less than 10 mSv) as well as the impact of tissue type and age. Low to moderate levels of radiation poses no risk to human health below a threshold comparable to natural radiation. The Academy also points out that approximately 40% of laboratory studies on cell cultures and animals report some sort of radiobiological hormesis. They state:

    “…its existence in the laboratory is beyond question and its mechanism of action appears well understood.”

    Meanwhile radiation protection agencies both international and national (outside of France) continue to assert that insufficient human data on radiation hormesis exists to supplant the Linear no-threshold model.(Cancer risks attributable to low doses of ionizing radiation: Assessing what we really know) They claim progressively larger epidemiological studies are required to quantify the risk to a useful degree of precision. For example, if the excess risk were proportional to the radiation dose, and if a sample size of 500 persons were needed to quantify the effect of a 1,000-mSv dose, then a sample size of 50,000 would be needed for a 100-mSv dose, and ≈5 million for a 10-mSv dose. In other words, to maintain statistical precision and power, the necessary sample size increases approximately as the inverse square of the dose. So to examine the dosage range of 1 to 5-mSv it would require a sample space of 100,000,000 subjects. This of course places any valid conclusion (by their standards) forever beyond reach, yet this is the rational behind continued official support of LNT models.

    In other words they have defined the problem in such a way that it cannot be solved to their satisfaction – ever- and then use this to justify continued application of linear extrapolation of risks to very low doses and claim it is appropriate.

    Now personally I don’t think that the case for radiation hormesis is complete ether, there is still more work to do, but give that there is certainly considerable experimental evidence for it But the supporters of the linear model are basically saying LNT must be accepted because we have determined that it is impossible to falsify by observation, and that is not an acceptable stand in my opinion. That is why I accept hormesis as a plausible hypothesis, and reject LNT as meaningless statement of ignorance.

    * I only linked to the last of this series


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  23. 23
    Carl Willis Says:

    But the supporters of the linear model are basically saying LNT must be accepted because we have determined that it is impossible to falsify by observation,

    I’m not sure which particular supporters you had in mind who espouse that view about infallibility. Not all supporters say that. Certainly SOME “supporters” (loosely speaking) exist who abuse or misinterpret the LNT idea (for example, to say that no radiation exposure is acceptable), but such arguments have no bearing on the scientific picture and should simply be ignored when the subject is LNT itself.

    LNT simply recognizes the trend, well-established in high-dose / high-dose-rate situations (the best human data we have), that excess radiation dose carries excess relative risk of carcinogenesis in humans, AND that within the limits of precision of this first-order relationship, extrapolated to low doses, the dose threshold for added risk is not different from zero. That’s it. I hope everyone can agree that’s what it is.

    The day may come when a threshold that is statistically different from zero is conclusively discerned from human cancer data. The day may come when low-dose data obviates the extrapolation of trends from high-dose data, or improves the precision enough to say that some trend of higher order than a line is supportable. LNT is eminently “falsifiable,” it just hasn’t been, according to authoritative scientific review that is well beyond the scope of the comments section on a blog.

    My whole beef revolves not around the scientific details of LNT but around the apparent urge among a few in this quarter to throw the baby (the scientific idea) out with the bathwater (the stuff certain idiots come up with when they misunderstand the idea).

    -Carl


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  24. 24
    DV82XL Says:

            Carl Willis said:

    Certainly SOME “supporters” (loosely speaking) exist who abuse or misinterpret the LNT idea (for example, to say that no radiation exposure is acceptable), but such arguments have no bearing on the scientific picture and should simply be ignored when the subject is LNT itself.

    But that is just the point. We are concerned with how LNT is interpreted by people like Helen Caldicott (“in terms of cancer risk, the only safe dose is no dose”) which is the simple conclusion that one must come to using LNT.

            Carl Willis said:

    LNT simply recognizes the trend, well-established in high-dose / high-dose-rate situations (the best human data we have), that excess radiation dose carries excess relative risk of carcinogenesis in humans, AND that within the limits of precision of this first-order relationship, extrapolated to low doses, the dose threshold for added risk is not different from zero. That’s it. I hope everyone can agree that’s what it is.

    Of course I agree with that as a explanation, however it is still more a statement of ignorance than anything else, and should be treated as such, not as the equivalent of saying that all radiation is dangerous however low the dose is. That however is how some idiots out telling women there is a risk of getting cancer from a breast x-ray, are using LNT as justification for saying so.

            Carl Willis said:

    The day may come when a threshold that is statistically different from zero is conclusively discerned from human cancer data. The day may come when low-dose data obviates the extrapolation of trends from high-dose data, or improves the precision enough to say that some trend of higher order than a line is supportable. LNT is eminently “falsifiable,” it just hasn’t been, according to authoritative scientific review that is well beyond the scope of the comments section on a blog.

    And it will never be – given the way the hypothesis has been framed Saying that it technically can be falsified is a pedantic irrelevance, if in practice it cannot be. At any rate your statement veers dangerously close to an appeal to authority, and that is not an acceptable argument on these pages.

            Carl Willis said:

    My whole beef revolves not around the scientific details of LNT but around the apparent urge among a few in this quarter to throw the baby (the scientific idea) out with the bathwater (the stuff certain idiots come up with when they misunderstand the idea).

    -Carl

    In my opinion the LNT hypothesis for low dose ionizing radiation does need revising. No mater how valid the assumptions were fifty years ago, a body of observations indicates that those assumptions were too narrow. This doesn’t mean that the LNT effect, in the universal sense is scientifically invalid, only that it should not apply in this case because it is not supported by the data.


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  25. 25
    Carl Willis Says:

    our statement veers dangerously close to an appeal to authority, and that is not an acceptable argument on these pages.

    I read this to mean that you, DV8… do not accept appeals to authority.

    Strikes me as odd.

    Let me just point out that any time somebody cites references, i.e. work done by others, they are making an appeal to authority. The assumption is that the person(s) who did the work is honest and knowledgeable enough about what they did that you can trust them on the subject. In the formal logical sense, it is fallacious to assume that someone else furnishes accurate information. Scientists can lie and they can make mistakes, and so just because they claim something does not make it accurate. But the alternative to putting some weight in other sources is to do the work yourself and trust only what you directly observe. Rather limiting. In school most of us learn about how to identify “reliable” sources. That is, how to make reliable appeals to authority. For instance, a textbook or a scientific committee report carry more weight than a non-peer-reviewed industry magazine article. Reliable sources can be inaccurate. But because we cannot do all the observing and conclusion-making ourselves in this world, we have to put some weight in what others say.

    Personally, I’d say the work of scientists reporting to NAS, the NCRP, the ICRP, UNSCEAR, and Eric Hall’s radiology text carry a lot of weight when it comes to collecting and interpreting data on the biological effects of radiation. You can ignore them as an appeal to authority if you wish, but if it’s the formal logical fallacy that bothers you, I’m surprised you see fit to cite references yourself.

    -Carl


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  26. 26
    Engineering Edgar Says:

    Even from LNT supporters, would it be possible to come to some consensus of a low level at which point it’s possibly not zero, but so close to zero that it’s not worth concern. For example, even if “as low as reasonably possible” is considered the outcome, what about simply saying “Anything that exposes members of the general public to bellow 10 mrem per year is so small that we should just forget it, because it’s not worth wasting our time worrying about”


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  27. 27
    DV82XL Says:

            Carl Willis said:

    our statement veers dangerously close to an appeal to authority, and that is not an acceptable argument on these pages.

    I read this to mean that you, DV8… do not accept appeals to authority.

    Strikes me as odd.
    -Carl

    Carl, if that’s all you can find wrong with what I have written, I cheerfully withdraw that statement.

    However I do question your wording in the passage under examination, because “LNT is eminently “falsifiable,” it just hasn’t been, according to authoritative scientific review that is well beyond the scope of the comments section on a blog.” scans like you are suggesting we take this assertion on the authority of the sources, prima facie. I was not sure you meant this which is why I qualified it with ‘veers dangerously close’.

    A misunderstanding only.


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  28. 28
    leg Says:

    Darn, late to the party again, but I’ve been swamped the last few days dealing with some interesting radioactive sources where I work. Anyway…

    Carl: That’s a fun web site you’ve set up. I’ve also enjoyed your comments here. Here are some of my comments on what you have said (based on 30 years as a health physicist principally in the medical/academic world).

    Be very cautious giving credit to the anti-nuclear folks for increasing safety in the nuclear industry. They will quote you out of context. Study a little more about the history of radiation safety and you will see that it goes a long ways back and there has been a steady progression of making it safer – long before the anti-nuke contingent arrived on the scene. Buzz0, and others here, are making the point that the LNT theory is flawed, which is a valid point. However, the anti-nuclear folks refuse to recognize its flaws and they use it in a fashion that is purposely designed to scare those who know little about radiation. I find this to be reprehensible and harmful to society. Buzz0′s reductio ad absurdum idea is a good way to counter such bull pucky and to educate the public at the same time. I’ve done some of the same in hundreds of public presentations and it can be quite effective in negating the anti-nulear jerks.

    I appreciate Dr. Hall’s book, but there is a LOT more radiobiology info out there. There is also a lot of information out there indicating the LNT’s flaws. Look up Bernie Cohen, Ph.D. ( http://www.phyast.pitt.edu/~blc/ ). Look up James Muckerheide( http://www.radscihealth.org/RSH/ ). Somewhere I read that there are at least 1500 scientific articles demonstrating that low doses of radiation have a beneficial effect. So there is no need to cherry pick anything – the science is out there and quite robust.

    Don’t forget that cells will have an adaptive response to any kind of assault – radiation included. This is the most likely reason the LNT theory fails at low dose risk projection. The theory does not account for this response (OT but it is kind of like global warming models that don’t account for solar forcings). In the last few years the radiation governing bodies, e.g ICRP, NCRP et cetera, have softened their language and concern about low dose radiation as more evidence points to little or no harmful effects (and maybe a nod to what the LNT theory does to harm the benficial uses of radiation because of its misuse by anti-nuclear types)

    I don’t have the procedure handy, but I’ll look for the one that describes an experiment with irradiating seeds (any kind). At low doses more seeds sprout and grow bigger when all other conditions are the same. At a certain point of higher activity (orders of magnitude higher than the LNT will predict) of course the seeds do not do well. It would be a good experiment to add to your web site.

    Got to go do some radiation safety training, but hope to get back to you again.


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  29. 29
    StephenT Says:

    I can’t believe that anyone falls for this LNT rubbish. The fact is that if you want to avoid low doses of radiation, you’re going to have to move to another planet, because this one is radioactive! Our species evolved in the presence of low level radiation and its part of our environment and the environment of every other species on the planet. There is radioactive material in soil, rocks, air water and the earth’s core, so can we please stop arguing about things that aren’t a problem and get on with solving the real problems of climate change, pollution and energy security. We need to have a debate about the real issues of nuclear energy so we can all accept that it isn’t the bogeyman its made out to be.


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  30. 30
    Chem Geek Gregor Says:

    The point here is that LNT is NOT a reason to oppose nuclear energy because the levels are trivial compared to other things. If you consider radiation the boogie man, then there are many things to be afraid of before nuclear reactors. Going after nuclear energy in the name of radiation exposure is like going after jay walkers in the name of reducing crime – you don’t obsess over the most minor offender to the exclusion of all others.


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  31. 31
    DV82XL Says:

    Keep in mind that Carl Willis is right to the extent that a logically valid hypothesis has been misinterpreted by policy makers and propagandists and we really should frame our criticisms to reflect that.

    Given the way it has been declared, the LNT hypothesis for low dose ionizing radiation, cannot be practically falsified, so ultimately it will remain a rule-of-thumb, or at best a statement of the upper bound where some minimal effect possibly might occur. This is the only scientifically justified interpretation. The problems arise when nit-wits who really have no idea what LNT is about or how to apply it start to run off at the mouth.

    At any rate we should be careful vilifying the hypothesis when we should be attacking the morons that are abusing it.


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  32. 32
    PJLindsey Says:

    What always got me chuckling was the dental asst placing a lead shot apron over me before a dental xray. Exactly how much shielding does that apron really provide? The only reason I can see is that it makes the patient feel protected.


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  33. 33
    StephenT Says:

    Point taken, the LNT hypothesis is not at fault for its desperate grasping-at-straws adoption by the anti-nuclear lobby. Who was it who said ‘there are lies, damned lies and statistics’.


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  34. 34
    [Other] Matthew Says:

            Carl Willis said:

    LNT simply recognizes the trend, well-established in high-dose / high-dose-rate situations (the best human data we have), that …

    Well then it’s not an LNT model, is it? If there is a distinction between ‘high dose’ and ‘low dose’ then the model is an L model. The NT part must be stripped because said distinction is a T by definition.

    To say “The LNT model is valid provided you are dealing with values above X” makes as much sense as referring to wealthy people below the poverty line, or square cirles with 7 sides.


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  35. 35
    DV82XL Says:

            [Other] Matthew said:

    To say “The LNT model is valid provided you are dealing with values above X” makes as much sense as referring to wealthy people below the poverty line, or square cirles with 7 sides.

    That’s not how the hypothesis is stated. In the end it’s just a back extrapolation down to zero that posits that because the known part of the curve is linear in terms of dose-response, the lower region will be as well all the way down.

    The beef many have with this is that it is not supported experimentally, nor can it be, and observed responses at lower doses show, in many cases, the opposite effect.


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  36. 36
    Carl Willis Says:

    Well then it’s not an LNT model, is it

    If you would rather call it a “linear threshold-not-statistically-different-from-zero model,” feel free. That kind of construction would get a brownie point for scientific rigor, while losing points for being a flat-out ridiculous name for something.

    If you don’t dispute the data and the analysis (and realistically you shouldn’t, unless you are confident in your expertise in epidemiology, statistics, and so on), then the point just seems to come down to semantics and matters of taste. De gustibus non disputandum est.

    -Carl


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  37. 37
    Carl Willis Says:

    On second thought, “linear no-threshold” is a completely appropriate name for a model, and you wouldn’t get any “brownie points for rigor” by renaming it. It is simply a model. The data behind it carry uncertainty.

    The model may be inaccurate at low doses, but has not been found to be so. The LNT model may be accurate at low doses because it has been found to be accurate at higher doses, and human epidemiological data continues to support it well at lower and lower doses (in utero exposure carries a significant risk of cancer induction at doses above 20 mGy, etc). Other empirical models may be fit to the data and be found to be accurate over some range of that data. More than one model may simultaneously be accurate for the same data. Some models may be higher order than linear, they may have thresholds, etc. The data has imprecision, and it is not possible yet to know which if any of these models best reflect the underlying reality. Some models are known to be inaccurate right now, for instance a model that predicts a threshold at greater than 10 rad:

    For most tumour types in experimental animals and in man a significant increase in risk is only detectable at doses above about 100 mGy. (UNSCEAR 2000, Annex G, par. 537)

    If there is a threshold, it is below about 10 rad. For workers in a facility like the one for which I function as RSO (among other duties), it is appropriate to say that the 2 rem we’re permitted to receive in a year doesn’t carry a statistically significant risk of cancer (reflecting imprecision in data); and it is also appropriate and entirely compatible to say that any exposure to radiation is thought to carry an increased risk of cancer (our simplest, most widely-accepted model for the data that is known to be accurate for the range in which we have data) and we should follow ALARA. In other words, as UNSCEAR 2000 puts it,

    there are no circumstances where it is scientifically valid to equate the absence of an observable biological effect with the absence of risk. (par. 539)

    -Carl


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  38. 38
    DV82XL Says:

            Carl Willis said:

    If you don’t dispute the data and the analysis (and realistically you shouldn’t, unless you are confident in your expertise in epidemiology, statistics, and so on), then the point just seems to come down to semantics and matters of taste. De gustibus non disputandum est.

    -Carl

    On the contrary it is the analysis that we do dispute. Even if data for higher exposures is not questioned, even though there should be more of it, the extrapolation down to zero is only justified statistically.

    However data from the low exposure region has been gathered, and it shows that the linear extrapolation breaks down, below a certain threshold so LNT is not applicable, no matter how justified the mathematics might be.

    The problem is that radiation protection regulators and other authorities will not recognize, and that is a political issue more than anything else.

            Carl Willis said:

    The model may be inaccurate at low doses, but has not been found to be so. The LNT model may be accurate at low doses because it has been found to be accurate at higher doses, and human epidemiological data continues to support it well at lower and lower doses

    The whole point of this debate is that the human epidemiological data does not. It fact it shows evidence of some sort of radiobiological hormesis. Compounding this is that the LNT has been stated in such a way it cannot be disproved except by experiments needing impractically huge sample spaces

            Carl Willis said:

    For workers in a facility like the one for which I function as RSO (among other duties),…

    Well there is the other shoe down, isn’t it Carl? That’s fine, you have to apply the regulations as they are written, but that does not make them right. Nor do those regulations make it right for radiophobes to tell people not to get x-rays, radiotherapy, eat irradiated food, or claim that spent fuel remains dangerous for tens of millions of years. Yet this is exactly how LNT is being misinterpreted out on the street.

    Worse this creates a problem for any regulator, who’s political masters are not going to permit the rules to be relaxed because of a feared backlash of public opinion and the lobbying of the radiation protection industry. And this is causing issues with the development and deployment of useful nuclear technologies.


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  39. 39
    Calli Arcale Says:

            drbuzz0 said:

    Of course this is not for radiation protection. They were showing the system at its extreme and the purpose is to avoid radar and make most surface to air weapons useless.

    Most SAM’s are not designed or programmed to go after a target that low and won’t be able to track it from ground clutter.

    Of course, if there was a low level threat to be avoided, the final shot showed the aircraft swing the wings all the way back, light the afterburners and take off at a steep angle up.

    Thing is, the ground-effect cargo plane (can’t remember its name at the moment) wouldn’t have that advantage. Slow, loud, clumsy, and about six *feet* off the ground. And totally unable to use things like canyons and forests for protection; if it tried that, the enemy would be the least of its worries. ;-)

    I seem to recall reading of an experimental light sport aircraft in the ground effect category. Well, I say light sport aircraft, but I think it actually got registered as a *boat* instead, because although it did technically lift off, it physically could not fly outside of ground effect. The upshot of such a vehicle was that if you had a bunch of money to spend but didn’t want to go to the effort of getting a pilot’s license, this technically-a-boat airplane would give you a chance to fly. I don’t think it caught on.


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  40. 40
    Carl Willis Says:

    On the contrary it is the analysis that we do dispute.

    We? I read this to mean that you, “DV82XL” (whom I presume is a single individual), dispute the analysis (of UNSCEAR, NCRP, etc.) That’s your right. However, there’s ample evidence that you misunderstand that analysis, or simply and inexplicably discount it in favor of less-comprehensive and / or outlying sources. For instance, what is the source of this comment?

    the human epidemiological data [...] shows evidence of some sort of radiobiological hormesis.

    The comprehensive expert analyses (e.g. UNSCEAR) do not ignore evidence of hormesis or threshold responses. Such evidence is weighed and considered on its merits, along with much other data. For some narrow situations threshold models are more accepted (e.g. risk of bone cancers from internal exposure to radium). My intention is to make sure that other readers understand that the comprehensive, mainstream, expert scientific analyses do look at the range of evidence, and on the basis of all of it, do not endorse hormesis or any threshold model of radiation risk as pertains to the general issue of external whole-body radiation exposure. Data and its analysis can be found in may places, but the logical places to start looking at these things are the broad, general, overviews of the field. I mentioned the major radiobiology textbook previously; also, Appendix G (“Biological Effects at Low Radiation Doses”) of UNSCEAR 2000 may be downloaded here:

    http://www.unscear.org/docs/reports/annexg.pdf

    Well there is the other shoe down, isn’t it Carl? That’s fine, you have to apply the regulations as they are written, but that does not make them right.

    Huh? I personally have not made any comment endorsing or opposing the regulations, or opining in any way on whether or not they are “right.” I could offer opinion and join the endless windbaggery, but I try not to. I’m on a little scientific literacy crusade, because on the basis of just a few comments above, I perceive some shortcomings in that department. That’s all.

    -Carl


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  41. 41
    DV82XL Says:

            Carl Willis said:

    On the contrary it is the analysis that we do dispute.

    We? I read this to mean that you, “DV82XL” (whom I presume is a single individual), dispute the analysis (of UNSCEAR, NCRP, etc.) That’s your right. However, there’s ample evidence that you misunderstand that analysis, or simply and inexplicably discount it in favor of less-comprehensive and / or outlying sources. For instance, what is the source of this comment?

    the human epidemiological data [...] shows evidence of some sort of radiobiological hormesis.

    The comprehensive expert analysis (e.g. UNSCEAR) do not ignore evidence of hormesis or threshold responses. Such evidence is weighed and considered on its merits, along with much other data.

    Carl, I made a point of linking to a list of papers supporting the hormesis hypothesis, and specifically to a report by France’s Académie des Sciences — Académie nationale de Médecine up thread, that would be considered source in any academic context that I can think of.

    I did not write the lead article in this section, nor are the other people commenting here with me in agreement with him sockpuppets of mine, so your attempt to try and isolate me as a lone voice against LNT fails on that alone, and there are many others out there that also feel this has gone too far.

            Carl Willis said:

    The comprehensive expert analysis (e.g. UNSCEAR) do not ignore evidence of hormesis or threshold responses. Such evidence is weighed and considered on its merits, along with much other data. For some narrow situations threshold models are more accepted (e.g. risk of bone cancers from internal exposure to radium).

    Objectors to LNT know what the party-line is Carl, the point is that there is a great suspicion that is is overly conservative due to political considerations, that is at the core of this debate. If you, or anyone else think,s this UN committee is any different from any other in that organization in that it is not motivated by the politics of its members more than by fact, I have some penny stock in a company that can make cars run on tap water you might be interested in.

            Carl Willis said:

    Well there is the other shoe down, isn’t it Carl? That’s fine, you have to apply the regulations as they are written, but that does not make them right.

    Huh? I personally have not made any comment endorsing or opposing the regulations, or opining in any way on whether or not they are “right.” I could offer opinion and join the endless windbaggery, but I try not to. I’m on a little scientific literacy crusade, because on the basis of just a few comments above, I perceive some shortcomings in that department. That’s all.

    -Carl

    Well I don’t know what you call support in this context, but it seems to me like your ‘scientific literacy crusade’ looks very much like support of the status quo, and the fact that you are a RSO is at the very least a potential conflict of interest in this debate, which you might have cleared up earlier on.

    At any rate the debate here should not be on the LNT as a hypothesis, I have tried to make this clear in several comments I have made up thread, only how it is used in the making of policy, and by the antinuclear movement. It is only in those contexts that LNT is misapplied


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  42. 42
    Carl Willis Says:

    On “I” versus “we”: unless DV82XL is a group of people, I would expect that entity to use the personal pronoun “I”. Maybe it is a group, but the writing sounds like an individual. Since Carl Willis is an individual, I use the pronoun “I”. Even when I perceive that others may substantially agree, I do not presume to speak for them when I am speaking for myself. Just a matter of clarity. Nothing to do with sockpuppetry or related nonsense.

    The rest of the discussion is going in circles now.

    To clarify my background: When I write something here, I speak for myself and don’t presume to speak for anyone else. I am a nuclear engineer for a particle accelerator company in New Mexico. A small ancillary duty is to manage the radiation safety program for that company, but that is neither a duty I aspired to nor was originally hired to carry out. I don’t find that occasional work to involve ideological indoctrination, subversion, or conspiracy to sap and impurify my precious bodily fluids. I am completing my doctorate in nuclear engineering at Ohio State. Relating to radiobiology, I have authored a couple little publications on mixed-field dosimetry for clonogenic assays and some of my academic research focus has been on boron-neutron capture therapy, but I don’t consider that background to be “expertise” in the context of the LNT controversy as compared to, say, the expertise at UNSCEAR or the NCRP or the French Academy of Sciences or Eric J. Hall. I advocate a high level of trust for professional scientists, especially from those whose expertise does not compare. Attempting to pawn off expert findings as being politically motivated, without direct and compelling evidence, is symptomatic of a broad constellation of anti-science superstition (anti-evolution, anti-climate-change, anti-vaccination, and so on). I see suspect language in that direction, and lots of misinterpretations, in this thread. I have done what I can to add the appropriate degree of balance, and I appreciate the opportunity.

    That’s it from me.

    -Carl


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  43. 43
    DV82XL Says:

    Carl, I have come to the conclusion that you are, despite your education, ether dense or pedantic to the point of being handicapped.

    It doesn’t appear that you understand what is being objected to in the criticisms being leveled against how LNT is used, or even to recognize that there is is a problem and that it extends beyond the rightness or wrongness of the LNT hypothesis or my personal opinions of it. Nor have you attempted to address them except with restatements of the positions that the regulators have taken on the matter.

    As for who to trust and not to trust, in this and every other topic it is best to recognize that we’re dealing with a spectrum of trust, among other things – trusting anyone to trusting no one. Credulity to cynicism. But not to indulge in reflexive centrism, but to find the healthiest point in this spectrum which is somewhere between the two ends. This being the case, it is pertinent to question even professional scientists to some extent and examine the rationale behind their positions, but never to accept or reject purely on the bases of presumed authority, what now you seem to be suggesting we do.

    Given this, it is impossible to have a productive discussion with you, and now it seems you were never interested in having one.


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  44. 44
    Robert Hargraves Says:

    LNT vs hormesis

    LNT extrapolators: How do you think vaccines work?


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  45. 45
    Neil craig Says:

            Carl Willis said:

    The model may be inaccurate at low doses, but has not been found to be so. The LNT model may be accurate at low doses because it has been found to be accurate at higher doses, and human epidemiological data continues to support it well (par. 539)

    -Carl

    That simply is not so. There is a large amount odata from Chernobyl where the 250,000 deaths predicted by LNT failed to happen, to the Cohen study showing a negative correlation with radon to the Taiwan apartments which saw a 97% reduction in cancers to the undisputable fact that natural background radiation is & always has been far higher in some parts of the world (eg Kerala, India where it is 17 times the safe limit) with no observed ill effects. See http://a-place-to-stand.blogspot.com/2010/03/low-level-radiation-evidence-that-it-is.html for these & others.

    By comparison can you produce any evidence for LNT at low levels, produced before or indeed after it was accepted as “science”?


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  46. 46
    soylent Says:

            PJLindsey said:

    What always got me chuckling was the dental asst placing a lead shot apron over me before a dental xray. Exactly how much shielding does that apron really provide? The only reason I can see is that it makes the patient feel protected.

    You’re thinking of gamma rays which are usually, but not always, far more energetic and penetrating than dental x-rays.

    The half-value layer for a 100 kV x-ray tube(which generates a spectrum of x-rays, with no x-rays above 100 keV) is ~0.3 mm in lead.


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  47. 47
    Bryan Elliott Says:

    Your character encoding problem is coming from the fact that your page is encoded as UTF-8, but the content is encoded as Windows Western (ISO-8859-1). I’m not sure how you accomplish this (given it’s WordPress). Check if your admin panel is UTF-8 encoded (in Chrome, click the menu button and scroll to “Tools -> Encoding”). If it is, make sure that the admin panel templates contain “”, and that your database encoding is also UTF-8.

    It’s trivial for me to fix my ability to read a post clearly, as a developer (same menu options), but most users won’t bother. It’s just a spit-and-polish thing, you know?


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  48. 48
    Anon Says:

    ISO-8859-1 is not a windows character encoding (windoze does not recognise the C1 control characters).

    But if you do set the encoding to unicode you see unknown character symbols in the text (or at least I do).

    The problem comes from a database restore that took place some time ago, all the old posts ended up with a character set problem.


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